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| United States Patent | 5,764,273 |
| Paoli | June 9, 1998 |
A method and apparatus for using a raster output scanner which includes an array of independently addressable light valve elements that control the slow scan direction position of a spot in an image plane. In operation, the array is illuminated by light from a separate optical source and disposed such that the spot from each element of the array impinges the image plane in a different position in the slow scan direction and such that the maximum distance between the spots is less than the distance between scan lines. Only a single element of the array passes light per scan line, thus only a single spot is formed on the image plane per scan line. Control of which element in the array transmits a light beam per scan line allows control of the spot position in the slow scan direction for that scan line.
| Inventors: | Paoli; Thomas L. (Los Altos, CA) |
| Assignee: | Xerox Corporation (Stamford, CT) |
| Appl. No.: | 574566 |
| Filed: | December 14, 1995 |
| Current U.S. Class: | 347/248; 347/234 |
| Intern'l Class: | B41J 002/435 |
| Field of Search: | 347/248,234,250,239,136 372/24 359/204 250/578.1 |
| 4040096 | Aug., 1977 | Starkweather | 358/302. |
| 4281904 | Aug., 1981 | Sprague et al. | 359/263. |
| 4445125 | Apr., 1984 | Scifres et al. | 247/237. |
| 4536778 | Aug., 1985 | De Schamphelaere et al. | 347/130. |
| 4600837 | Jul., 1986 | DeStefano et al. | 250/235. |
| 4651169 | Mar., 1987 | Muka | 347/261. |
| 4651170 | Mar., 1987 | Chandler et al. | 347/259. |
| 4802182 | Jan., 1989 | Thornton et al. | 372/50. |
| 4845725 | Jul., 1989 | Welch et al. | 372/46. |
| 4864326 | Sep., 1989 | Kawamura et al. | 347/240. |
| 4870652 | Sep., 1989 | Thornton | 372/50. |
| 4925276 | May., 1990 | McMurray et al. | 359/67. |
| 5047789 | Sep., 1991 | Konayama et al. | 347/232. |
| 5049897 | Sep., 1991 | Ng. | |
| 5138339 | Aug., 1992 | Curry et al. | 347/239. |
| 5574491 | Nov., 1996 | Paoli | 347/248. |
| Foreign Patent Documents | |||
| 22 20018 | Sep., 1990 | JP. | |
Bestenreiner, F.; Greis, U.; Helmberger, J.; and Stadler, K., "Visibility and Correction of Periodic Interference Structures in Line-by-Line Recorded Images," Journal of Applied Photographic Engineering, 2:2, Spring 1976, pp. 86-92. Filinski, I. and Skettrup, T., "Fast Dispersive Beam Deflectors and Modulators," IEEE Journal of Quantum Electronics, QE-18:7, Jul. 1982, pp. 1059-1062. Sprague, R. A.; Urbach, J. C.; and Fisli, T. S., "Advances in Laser and E-O Printing Technology," Laser Focus/Electro-Optics, Oct. 1983, pp. 101-109. Thornton, R. L.; Burnham, R. D.; and Paoli, T. L., "Low Threshold Planar Buried Heterostructure Lasers Fabricated by Impurity-Induced Disordering," App. Phys. Lett., vol. Y7, No. 12, 1986, pp. 1239-1241. Urbach, J. C.; Fisli, T. S.; and Starkweather, G. K., "Laser Scanning for Electronic Printing," Proceedings of the IEEE, 70:6, Jun. 1982, pp. 597-618. |
TABLE I
______________________________________
.alpha. for Effective
position slow-scan
Optical
control =
2b spot size
mag in
Line Density/ 0.1 line (2a =
on valve =
slow-scan
Line Spacing
d spacing 2 .mu.m)
25 direction
______________________________________
300 lpi/84.7 .mu.m
3 .mu.m 86.18 2 .mu.m
2 .mu.m
42.4
4 .mu.m 87.13 2 .mu.m
2 .mu.m
42.4
5 .mu.m 87.71 2 .mu.m
2 .mu.m
42.4
10 .mu.m
88.85 2 .mu.m
2 .mu.m
42.4
600 lpi/42.3 .mu.m
3 .mu.m 86.18 2 .mu.m
2 .mu.m
21.2
4 .mu.m 87.13 2 .mu.m
2 .mu.m
21.2
5 .mu.m 87.71 2 .mu.m
2 .mu.m
21.2
10 .mu.m
88.85 2 .mu.m
2 .mu.m
21.2
1000 lpi/25.2 .mu.m
3 .mu.m 86.18 2 .mu.m
2 .mu.m
12.6
4 .mu.m 87.13 2 .mu.m
2 .mu.m
12.6
5 .mu.m 87.71 2 .mu.m
2 .mu.m
12.6
10 .mu.m
88.85 2 .mu.m
2 .mu.m
12.6
1200 lpi/21.15 .mu.m
3 .mu.m 86.18 2 .mu.m
2 .mu.m
10.6
4 .mu.m 87.13 2 .mu.m
2 .mu.m
10.6
5 .mu.m 87.71 2 .mu.m
2 .mu.m
10.6
10 .mu.m
88.85 2 .mu.m
2 .mu.m
10.6
______________________________________
TABLE II
______________________________________
.alpha. for Effective
position slow-scan
Optical
Line control =
2b spot size
mag in
Density/ 0.1 line (2a = on valve =
slow-scan
Line Spacing
d spacing 2 .mu.m)
25 direction
______________________________________
300 lpi/
3 .mu.m 86.1 6 .mu.m
2.03600 .mu.m
41.6
84.7 .mu.m 83.0 25.2 .mu.m
3.65682 .mu.m
23.2
4 .mu.m 87.1 6 .mu.m
2.02038 .mu.m
41.9
85.7 30 .mu.m
3.00618 .mu.m
28.2
5 .mu.m 87.7 6 .mu.m
2.01284 .mu.m
42.1
87.1 30 .mu.m
2.50680 .mu.m
33.8
10 .mu.m
88.85 6 .mu.m
2.00322 .mu.m
42.3
600 lpi/
3 .mu.m 86.1 6 .mu.m
2.03600 .mu.m
20.8
42.3 .mu.m 84.9 20 .mu.m
2.67006 .mu.m
15.8
4 .mu.m 87.1 6 .mu.m
2.02038 .mu.m
20.9
85.7 30 .mu.m
3.00618 .mu.m
14.1
5 .mu.m 87.7 6 .mu.m
2.01284 .mu.m
21.0
87.1 30 .mu.m
2.50680 .mu.m
16.9
10 .mu.m
88.85 6 .mu.m
2.00322 .mu.m
21.1
1000 lpi/
3 .mu.m 86.1 6 .mu.m
2.03600 .mu.m
12.4
25.2 .mu.m 84.9 20 .mu.m
2.67006 .mu.m
9.4
83.0 25.2 .mu.m
3.65682 .mu.m
6.9
4 .mu.m 87.1 6 .mu.m
2.02038 .mu.m
12.5
86.7 20 .mu.m
2.30482 .mu.m
10.9
85.7 30 .mu.m
3.00618 .mu.m
8.4
5 .mu.m 87.7 6 .mu.m
2.01284 .mu.m
12.5
87.1 30 .mu.m
2.50680 .mu.m
10.1
10 .mu.m
88.85 6 .mu.m
2.00322 .mu.m
12.6
1200 lpi/
3 .mu.m 86.1 6 .mu.m
2.03600 .mu.m
10.4
21.15 .mu.m 84.9 20 .mu.m
2.67006 .mu.m
7.9
83.0 25.2 .mu.m
3.65682 .mu.m
5.8
4 .mu.m 87.1 6 .mu.m
2.02038 .mu.m
10.5
85.7 30 .mu.m
3.00618 .mu.m
7.0
5 .mu.m 87.7 6 .mu.m
2.01284 .mu.m
10.5
87.1 30 .mu.m
2.50680 .mu.m
8.4
10 .mu.m
88.85 6 .mu.m
2.00322 .mu.m
10.6
______________________________________
TABLE III
______________________________________
.alpha. for Effective
position slow-scan
Optical
control =
2b spot size
mag in
Line Resolution/ 0.1 line (2a = on valve =
slow-scan
Raster Spacing
d spacing 2 .mu.m)
25 direction
______________________________________
300 lpi/84.7 .mu.m
3 .mu.m
0 30 .mu.m
30 .mu.m
2.8
600 lpi/42.3 .mu.m
3 .mu.m
0 30 .mu.m
30 .mu.m
1.4
1000 lpi/25.2 .mu.m
2 .mu.m
0 20 .mu.m
20 .mu.m
1.26
1200 lpi/21.15 .mu.m
2 .mu.m
0 20 .mu.m
20 .mu.m
1.06
______________________________________